Abstract: Several force sensor assemblies are disposed within a vehicle seat to determine seat loading and assist in safety device activation. Each force sensor assembly has a sealed body filled with a liquid or a gel. A pressure transducer, together with a supporting integrated circuit, is positioned to respond to the pressure of the liquid or gel. Loads are applied to the pressure transducer through the gel by a piston riding within the body. Compressive loads are thereby transformed into a pressure on the sensor and its support electronics, resulting in a low cost, accurate, and durable sensor. The sensor functions well for relatively low loads of less than a few hundred pounds.